Search

Layered hybrid organic–inorganic metal‐halide perovskites (HOIPs) can acquire chirality from molecules incorporated into their structure showing exciting possibilities in optoelectronics and spintronics. However, researchers have focused their attention on the study of bulk compounds, namely unstable and toxic Pb HOIPs. Herein, the chiroptical properties of R‐ and S‐β‐methylphenethylammonium Mn chloride HOIPs are reported in both the bulk and the few‐layer limit as exfoliated flakes. Red photoluminescence (PL) emission originating from the octahedrally coordinated Mn2+ is observed, with a PL shift to longer wavelengths when passing from bulk to flakes. Circular dichroism and circularly polarized PL mirrored‐signals for enantiomers are found in bulk samples, while in flakes, a degree of circularly polarized emission (P) of up to 17% at 80 K is achieved, comparable to Pb‐based HOIPs. Moreover, angle‐resolved PL measurements on flakes show that the PL emission and P are isotropic. These findings highlight the potential of these HOIPs from bulk to flakes for spin‐optoelectronic applications. [ABSTRACT FROM AUTHOR]

Stimuli‐responsive, optically‐active colloidal systems are convenient signal transducers capable of monitoring environmental changes at the nanoscale. We report on the coupling of chemo‐thermal cycloaddition reaction with temperature‐sensitive, DNA‐coated gold nanoparticles. We found that the concentration of chemical fuel, dictating the temperature of the mixture, is a primary ingredient in controlling the extent of the reversible clustering of gold nanoparticles. Our results show that rational coupling of chemical and colloidal systems can open up new possibilities in tracking the change of local temperature using aggregation/redispersion of nanoparticles. [ABSTRACT FROM AUTHOR]

In a first instance, the effect of the microwave irradiation on the 1,3‐Dioxa‐[3,3]‐sigmatropic rearrangement of aryl allylic carbamates was investigated. Under these new conditions, the reaction acceleration was clearly highlighted compared to conventional heating conditions. Depending on the electronic nature of substituents on the aromatic group, this type of rearrangement can be faster with similar or improved yields. Due to this experimental improvement, the diversity of aryl allylic carbamates able to undergo this rearrangement in a reasonable reaction time (30 min.) and with acceptable to high yields was greatly extended. Finally, an original synthetic way involving this microwave‐assisted process to access new six‐membered heterocyclic structures such as (E)‐5‐arylidene‐1,3‐oxazinane‐2,4‐diones was developed from Morita‐Baylis‐Hillman (MBH) adducts showing the interest of this molecular rearrangement approach. DFT and Fragment Distortion studies showed in general polar transition structures and connected high deformation and interaction energies with lower activation barriers. [ABSTRACT FROM AUTHOR]

The presence of a secondary phase between the fibres and the matrix has proved to be a good approach for interphase tailoring for enhanced load transfer. In this regard, an optimization of the low-temperature hydrothermal growth process of ZnO-nanorods on different basalt substrates as a function of different growth times was performed. Scanning electron microscope and X-ray diffraction analysis revealed the best results in terms of homogeneity and uniformity of the ZnO nanostructures for the longest growth time, i.e., 5 h for basalt fabrics and 120 minutes for single basalt fibres. The presence of ZnO nanostructures induced a hydrophobic behaviour with contact angles up to 116° for 4- and 5-h growth processes. Fibre/matrix adhesion was characterized by single fibre pull-out tests, showing a 16% increase in interfacial strength. ZnOs added also photocatalytic properties to basalt fibres, enabling a selective removal of organic pollutant equal to 37%. [ABSTRACT FROM AUTHOR]

This document, published in the journal Angewandte Chemie, highlights several research findings in the field of chemistry. One study discusses the synthesis of enantiopure irida[6]helicenes, which exhibit mirrored electronic circular dichroism and circularly polarized phosphorescence signals. Another study explores the use of the CF3 group as a synthon in palladium chemistry. Additionally, researchers demonstrate a selective shift in energy storage mechanism in aqueous aluminum-ion batteries through the engineering of oxygen vacancies in the α-MoO3 structure. Lastly, a scientific perspective proposes a unified set of triple E priorities (environment, economy, equity) to guide efforts in sustainable chemistry. [Extracted from the article]